Objective radiologic analysis of ground-glass opacity aimed at curative limited resection for small peripheral non-small cell lung cancer

Objective: The aim of this study was to evaluate the efficacy of the objective radiologic analysis of high-resolution computed tomographic images of small peripheral non-small cell lung cancer and to select the candidates for curative limited resection. Methods: High-resolution computed tomographic images of 146 surgically resected T1 N0 M0 peripheral non-small cell lung cancers were analyzed by using National Institutes of Health image software and classified on the basis of the percentage of ground-glass opacity within the tumor. Results: Eighty-seven percent of tumors with ground-glass opacity ratios of 90% to 100% (type I) were diagnosed as noninvasive bronchioloalveolar carcinoma, whereas 55.6% of tumors with ground-glass opacity ratios of 50% to 89% (type II) consisted of adenocarcinoma. Tumors with ground-glass opacity ratios of 50% or more (type I/II) had no nodal involvement, whereas nodal metastases were identified in 20.0% of tumors with ground-Glass opacity ratios of 10% to 49% (type III) and 24.4% of tumors with ground-glass opacity ratios of less than 10% (type IV). No tumors with ground-glass opacity ratios of 50% or more showed vessel infiltration, except for one lesion with a ground-glass opacity ratio of 50%. The 3-year disease-free survival was 97.7% for type I/II, 86.1% for type III, and 78.5% for type IV tumors. Conclusions: The objective quantitative radiologic analysis with National Institutes of Health image software exhibited a good correlation with the histologic classification, pathologic invasiveness, and postoperative outcome of small peripheral lung cancer. Patients with tumors that have ground-glass opacity ratios of greater than 50% are considered to be possible candidates for limited pulmonary resection.